Coil annealing furnace



t man Notiz, 1938 2,137,869

UNITED STATESv PATENT oFFlcE COIL ANNEALING FUBNAC James C. Woodson, Cleveland, Ohio, assigner to Lee Wilson Sales Corporation, Cleveland, Ohio, a corporation of Ohio Application. september z, 1931, sean No. mais:

a claims. (c1. zas-) This invention relates to a furnace for the heat and carried on radially disposed beams I6 which treatment of material in coils. particularly to the rest on a suitable foundation I1. A conical skirt annealing of steel or other metallic strip. I8 depends from the plate I3. The skirt I8, to-

In one type of coil annealing furnace which gether with an annular bottom ring I9, and a 5 has beenproposed heretofore, a base o n which peripheral outer side wall 20 defines a sealing 5 the coil was disposed for heat treatment was channel 2| extending around the base but posiadapted to receive an inner protective cover tioned below the latter. having van out-turned horizontal flange adjacent A coil supporting casting 22 is disposed on the its bottom, and a heating cover adapted to rest on refractory portion of the hearth and has a cirsaid flange. The lower portion of the inner cover cular opening 22 therein. Coils are disposed on 10 of such furnace is thus rmly held circumferenthe casting 22, as indicated at 24. A circulating tially and expansion and contraction due to heatfan 25 is Journaled in bearings embedded in the ing and cooling of the furnace cause a considerrefractory portion of the base or supported thereable degree of warping of the inner cover. from on a ring 28. A motor 21 is also carried on ll I have invented a novel coil annealing furnace the ring and is directly connected to the fan. l5 which overcomes the forementioned objection to A protective cover 28 has a circumferentially the device of the prior art described above and cylindrical upper side wall and dished top 29. is characterized by additional features of nov- The lower portion of the side wall of the cover elty and utility. In accordance with my invenflares outwardly as at lll. to conform with the 20 tion I provide a base adapted to receive a coil or frusto-conical shape of the refractory portion of 20 a plurality of coils. A 'sealing channel extends the base. The downwardly flaring portion 30 of around the base at a level below the latter, prothe cover terminates in a cylindrical lower edge viding a seat for the lower edge of an inner pro- II adapted to seat in the sealing channel 2|. tective cover. A heating cover is adapted to be The heating cover I2 comprises a refractory 2li disposed over the protective cover and the base. side wall and roof assembled within a structural 25 I provide a support for the heating cover indeframe including members 22 and sheet metal pendent of the base on which the coils are suppanels Il. Heat exchange tubes 34 are spaced ported. The heating cover has an inward flange circumferentially vabout the side wall of the heatadjacent its bottom extending toward the base, ing cover, each tube having a burner 36 in its a0 but clearance is provided between the base and lower end. The burners 25 are connected to a 80 the flange, and the lower portion of the protecfuel supply header 2l, and igniter electrodes 31 tive cover yextends through this annular space. are mounted adjacent each burner for initiating The inner cover is free to expand and contract combustion of fuel issuing therefrom without binding. thus preventing 'warping or A flange 2l of refractory material extends in- A as other injury to the cover. wardiy from the lower edge of the cover I2, to- 35 For a complete understanding (if the invenward the base-II. The cover is provided with a tion, reference-is made to the accompanying bottom ring 22 adapted to seat on an annular drawing, illustrating a present preferred embodisupport composed 01' a channel 40 bent t0 cirment, and. to the following detailed description cular form resting 0n circumferentially spaced 40 which is to be read in connection therewith. f columns 4I. The columns 4I extend upwardly 40 In the drawing: from the foundation II. The latter constitutes a The single gure is a vertical transversey seccommon footing for the columns 4I and beams tion through a coil annealing furnace according IQ, but the structures carried thereon for supto my invention. porting the cover I2 and base II, respectively,

4I Certain features of the furnace are repeated Me. nevertheless, independent 0f each Other- 45 about the circumference thereof, but showings In describing the manner of using the struc- 'of sch elements are omitted for the sake of ture explained above, it will be assumed that the clearness. heating cover I2 and the protective cover 28 have p Referring now in detail to the drawing, a furboth been removed from the positions in which so nace indicated generally by the numeral In comthey are shown. and a coil such as that shown prises a base or hearth II and a heating cover at 24 is disposed on the supporting casting 22. I2 adapted to be lowered-thereover. The hearth It will be understood that a plurality of coils of Il is composed of refractory brick-laid on a botrelatively narrowstrip may be so positioned on tom sheet I I, supported by columns Il, and web the casting as to occupy the same space as the plates Il, spaced circumferentially of the base single coil 22 of relatively wide strip. The pro- 55 tective cover 28 is then replaced and finally the heating cover I2, the covers being most conveniently handled by means of an overhead crane. Fuel is then delivered to the burners and ignited by sparks from the electrodes 31. The fan 25 is driven during the heating portion of the cycle to accelerate absorption of the heat by the coil through the protective cover. Any desired type of inert or non-oxidizing atmosphere may be supplied within the protective cover 28, by known means. It will be apparent that the space dened by the bottom plate I3, the skirt Il and the protective cover 2l may be made entirely gas tight, the sealing material in the channel, which may be either liquid or granular, eiectively sealing the space between the lower edge of the cover and the skirt il. Since the channel 2i is outside the furnace, liquid sealing material, such as oil, may be employed. When the coil 24 has been heated to the desired temperature, the heating cover i2 is removed and deposited over a fresh coil resting on another base similar to that shown at Il and enclosed within its own protective cover. The coil 24 is permitted to cool slowly in the atmosphere provided within the cover 28, the latter protecting the coil against contact with the atmosphere.

As will be apparent from the drawing, the lower portion of the protective cover extends through an annular clearance space between the base Ii and the inward bottom flange ll of the heating cover I2. The latter does not rest on the base but on the supporting ring Il which is spaced outwardly from the base. 'Ihe cover 2l has full opportunity of expanding and contracting freely as a result of the different temperatures which exist in various portions thereof, without binding, warping, or other injurious effects.

Although I have illustrated and described herein but one preferred form of the invention it will be understood that changes in the construction described may be made without departing from the spirit of the invention or the scope of the appended claims. As an example oi' such changes, the base and covers could be made square or rectangular in plan instead of the preferred cylindrical form shown in the drawing.

I claim:

1. A furnace comprising a charge-supporting base having a refractory layer thereon and a heating cover having a refractory lining therein, said cover being adapted to be lowered over said base, the portions of said lawer and lining which are adjacent when the cover is in cooperative position over said base being shaped and dimensioned to provide a frusta-conical clearance space therebetween, a sealing channel extending around said base and spaced radially outward of the margin of said layer, and a protective cover adapted to be disposed over said oase before the heating cover is lowered thereover, said protective cover having a portion adjacent its bottom edge shaped to fit in said space when said edge is seated in said channel.

2. A furnace comprising a base adapted to support a charge, a sealing channel below said base and extending therearound, a protective cover adapted to be disposed over the charge with its lower edge in said channel, and a heating cover adapted to be lowered over said protective cover, said heating cover having an inwardly projecting bottom ange approaching said base, the adjacent surfaces of said base and flange being frusto-conical and providing a similarly shaped annular space therebetween, the wall of said protective cover extending through said space.

3. In a furnace, a base adapted to support a charge, a portable heating cover adapted to be lowered over said base, a foundation, a series of columns extending upwardly therefrom for supporting said cover, a second series of columns spaced ouwardly from the first series for supporting the base on said foundation, a sealing channel between said series of columns, and a protective cover adapted to overlie a charge on said base and extending downwardly below said base through an annular space between it and said heatingV cover into said channel.

JADES C. WOODSON. 

